##article.abstract##
This paper presents a methodology for solving the hydrothermal dispatch problem when environmental impacts considered. The solution is obtained through a high order interior point model for optimization that considers power flow (DC Model) constraints, reservoir and generation limits, as well as emission reduction. The goal is to minimize both emissions and costs, which becomes a multiobjective problem considering that both objectives are in conflict. To face this fact, a weighted sum method is used in order to obtain a Pareto optimal set of solutions so they can be analyzed by a decision maker. A 6-bus test system with two hydroelectric plants and two thermal plants is used to show the obtained results